On August 13, 2024, NIST published the first three post-quantum cryptography standards, two of them developed by IBM researchers with partners, according to an IBM newsroom release, because quantum computers with enough power could break encryption such as RSA that protects most of the world’s data. That one fact explains why quantum computing explained in plain English matters outside the lab.
This guide gives a simple explanation of quantum computing: what a qubit is, what superposition and entanglement mean, what quantum computers might do, what they cannot yet do, and why security teams are preparing now. It draws on an IBM release and a guide from Oxford Quantum Circuits.
Quantum Computing in One Paragraph
A normal computer stores information as bits that are either 0 or 1. A quantum computer uses qubits, short for quantum bits, which Oxford Quantum Circuits calls the foundational unit of information in quantum computing. Because of the rules of quantum physics, qubits can be arranged in ways bits cannot, and that lets certain algorithms reach answers faster.
That is the whole idea. A quantum computer is not a faster laptop. It is a different kind of machine that is good at specific problems.
Qubits Explained, Simply
A bit is like a light switch: on or off. A qubit is more like a dimmer that can sit between the two settings until you measure it. Quantum algorithms use that flexibility to explore many possibilities in a structured way.
| Term | Plain-English meaning | Why it matters |
|---|---|---|
| Bit | Switch that is on or off | The unit of ordinary computing |
| Qubit | Quantum bit that can be in a mix of states | The unit of quantum computing |
| Superposition | A qubit being in more than one state until measured | Lets algorithms handle many possibilities together |
| Entanglement | Qubits linked so the state of one relates to another | Helps qubits work together |
| Quantum gate | An operation that changes qubit states | The building block of quantum algorithms |
OQC describes the use of qubits in superposition as what gives quantum algorithms their capacity to work faster on some tasks. The analogies above are simplifications.
What Quantum Computers May Be Good At
OQC says quantum computing could affect fields such as financial services, pharmaceuticals, operations and logistics, and security through faster and more nuanced information processing. It gives no specific results.
| Area | Possible use (OQC) | Status |
|---|---|---|
| Pharmaceuticals | Better simulation of molecules | Research |
| Financial services | Complex optimisation and risk | Research |
| Logistics | Route and schedule optimisation | Research |
| Security | Breaking and building encryption | Standards already published |
The statuses are our summary. OQC notes that quantum algorithms are hard to develop and program, and that the most promising applications are hard to identify.
What Quantum Computers Cannot Do Yet
Quantum computers are not ready to replace the computer on your desk, and they are not better at everyday tasks such as email or games. Building and programming them is difficult, and research is ongoing.
Headlines about breakthroughs are common, but practical, broadly useful quantum machines remain a work in progress. For a view of the global competition, read our overview of the quantum computing race.
Why Encryption Is at Risk
IBM’s release says quantum computers are progressing towards what it calls cryptographic relevancy, and that with enough computational power they could break encryption standards that protect most of the world’s data and infrastructure. It names RSA as an example of a widely used scheme at risk.
| Standard published by NIST (August 13, 2024) | Original name |
|---|---|
| ML-KEM | CRYSTALS-Kyber |
| ML-DSA | CRYSTALS-Dilithium |
| SLH-DSA | SPHINCS+ |
IBM adds that FN-DSA, originally FALCON, was selected for future standardisation but was not among the first three. Our guide to the quantum cybersecurity threat and Q-Day migration explains what organisations can do now.
What Ordinary People Should Do
You do not need to buy anything. Keep your devices and apps updated, because software makers will adopt the new standards over time. Use strong, unique passwords and enable two-factor authentication, since those habits protect you from far more common threats today.
If you manage systems at work, ask your IT team about their plan for post-quantum cryptography. IBM describes a roadmap with three phases of discovery, observation and transformation, and a Cryptography Bill of Materials to list cryptographic assets.
